Cathode energized by alternating or pulsating currents



March 19, 1929. 'RQSENBAUM 1,705,683

CATHODE ENERGIZED BY ALTERNATING OR PULSATING CURRENTS Filed Sept. 1921WITNESSES: I INVENTOR bruno fiose baum Patented Mar. 19, 1929.

UNITED STATES PATENT OFFICE.

BRUNO ROSENBAUM, OF BERLIN, GERMANY, ASSIGNOR T0 WESTINGHOUSE ELECTRIC&; MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CATHODE ENERGIZED. BY ALTERNATING OR PULSATING CURRIEN'IS.

Application filed September 2, 1921, Serial No. 498,183, and in GermanyFebruary 12, 1919.

This invention relates to a means for heating the cathode in athermionic device.

It. is an object of this invention to provide means through which theheat may be supplied by alternating current or by current containing analternating component, without causing corresponding noise in thetelephones of the signal system.

It is a further object of this invention to cause the filament of athermionic device to be heated without direct application of the heatingcurrent thereto.

Other objects of the invention, together with structural .details of thedevice, will be apparent from the following description and theaccompanying drawing which consists of a single figure diagrammaticallyillustrating the structure.

The drawing shows a vacuum device 1 having a cathode 2 which issupported by a press 3. A grid 4 and an anode 5 are shown supported byanother press 6 and located in close proximity to a portion of thecathode 2. The cathode is surrounded by a mass 7 of good heat-conductingmaterial, preferably metal. This is supported in any desired manner, forexample, by standards 8 entering the press 3. Themass 7 has a passage 9through it for accommodating the cathode 2 so that the metallic mass 7is insulated from the cathode and yet is in close proximity thereto. Themass 7 is surrounded by a coil 11 which is supplied through leads 12that extend through the press. These leads are supplied with currentfrom a source 13. A lead 15 for the grid 4 and a lead 16 for the anode 5are shown extending through the opposite press 6.

In the operation of the device, current from the source 13 is deliveredover the leads 12 to the coil 11 and heats this coil. It also heats themass 7 partly by direct flow of heat from the coil 11 into this mass andpartly by induction currents set up therein. The hot mass 7 heats thefilament 2. The heat is transferred from the mass 7 to the filament 2principally by radiation. The vessel 1 being evacuated, very littletransfer by convection takes place and the mass 7 being separated fromthe filament 2, practically no heat conduction. occurs between them. Theradiation is, however, enough to heat the filament strongly because aconsiderable length of the filament is in close proximity to the mass 7.

The hot filament 2 emits electrons which pass to the anode 5. The flowof these electrons is controlled by the rid 4. The external. connectionsto the lament, grid and anode are varied according to the use to whichthe vacuum device is. put. These connections are not illustrated and arenot further described because the invention is equally applicable to alltubes however used.

It will be understood that many details of the construction may bevaried through a wide range without departing from the principle of thisinvention. I, therefore, do not intend that the patent shall be limitedexcept as necessitated by the prior art or indicated by the claims.

I claim as my invention:

1. In a thermionic device, a thermally conductive member at least oneportion of which is adapted to emit electrons when hot, means includinga body of large thermal capacity around said thermally conductivemember, and a heating coil surrounding said body for heating at leastone portion of said thermally conductive member, and means cooperatingwith that portion of the thermally conductive member which emitselectrons to form a spacecurrent device.

2. In a thermionic device, a cathode, a heating member in proximity tosaid cathode and a heating coil surrounding said member.

In testimony whereof I afiix my signature.

BRUNO ROSENBAUM.

